Google Inc. sees self-driving cars being available to consumers in three to five years. Regulators and the insurance industry aren’t so sure it can happen that quickly.

Software and electronic sensors couldn’t fail and would have to anticipate and react like a human. States may have to decide how to license machines rather than people. Insurance companies have to reassess how to assign fault after accidents. Safety standards have to be rewritten to focus on electronics along with mechanics.

“The improvement can be such that we can make cars that drive safer than people do,” Anthony Levandowski, product manager for Google’s self-driving car technology, told a Society of Automotive Engineers meeting in Washington last week. “I can’t tell you you’ll be able to have a Google car in your garage next year. We expect to release the technology in the next five years. In what form it gets released is still to be determined.”

U.S. auto-safety regulators are eager to reap the safety benefits that may come from taking human error out of driving. About 33,000 people die annually in traffic crashes in the U.S., with that number falling yet killing almost as many people each year as suicide.

“It’s going to make a huge difference in reducing crashes overall,” Stickland said in an interview.

Road Tests

While crash-avoidance systems that can alert a driver or apply brakes in advance of a wreck are coming to cars now, autonomous vehicles “are a long way off,” he said.

The self-driving car is among projects stemming from Google’s practice of letting employees develop ideas not necessarily tied to online search and digital advertising. The car is allowed on public roads for testing purposes in Nevada, California and Florida.

Google hasn’t indicated interest in producing the cars for sale. “Our focus is on the technology itself,” Jay Nancarrow, a spokesman, said in an e-mail.

The company has demonstrated it on the streets of Washington and other cities where it might need to win favor for such a car to be considered road-worthy. Google also established a connection with regulators by hiring Ronald Medford, NHTSA’s deputy director under Strickland, as of last month as director of safety for the self-driving car.

Levandowski, who helped design the self-driving car, says Google’s biggest challenge is ensuring reliability of the software that makes the car drive, because a failure would mean nothing is controlling the vehicle.

“We’re really focusing on building in the reliability so we can trust and understand the system will perform safely in all conditions,” Levandowski said. “How can you trust the system? How do you know how it can perform? How do you design it with proper processes in order to understand and minimize failure? How do you bake into a car redundant braking?”

In a car driven by a person, if the power steering fails or a light goes off, a person would be in control to figure out what to do. A self-driving car would need to be taught how to respond to all sorts of scenarios that may occur with little to no room for error.

Such cars would also need to acquire the sort of judgment a person would have to know that a ball rolling into a street may be followed by a small child running after it.

‘Massive Challenge’

NHTSA enforces vehicle safety standards that govern the minimum performance everything from the design of windshield wipers to internal trunk releases. Some of the standards date to the agency’s creation in the 1970s.

The agency would need to create standards for electronics of a self-driving car and figure out how to test them, said Dan Smith, associate administrator for vehicle safety.

“It gets to be a massive challenge to figure out how will the government come up with a performance standard that is objective and testable for so many different scenarios where failure could possibly occur,” Smith said at the SAE panel. “Part of that has to do with if we should be looking at the underlying electronics.”

The National Academy of Sciences, in a report a year ago, said NHTSA must “become more familiar with and engaged in” setting automotive-electronics standards in existing cars, without mentioning the potential of self-driving technology.

Deciding Fault

The insurance industry, which has given drivers discounts on premiums for new auto technologies such as air bags, says it would similarly promote safety advances from self-driving cars. Still, it would have to decide whether it can assign liability to a company, or a piece of software, after an accident.

“It’s a legal morass right now, and unfortunately it will take court decisions to work this out,” Robert Hartwig, president of the Insurance Information Institute, a New York- based industry group, said on the SAE panel.

“Right behind the first autonomous vehicle is the first autonomous vehicle ambulance chaser,” he said. “They will be there faster than you can imagine looking for any sort of accident that might be attributable to a deep pocket.”

Hartwig predicts it will take 15 to 20 years for truly autonomous vehicles to populate U.S. roads. Chuck Gulash, senior executive engineer of Toyota Motor Corp.’s technical center in Ann Arbor, Michigan, said the industry may not get all the way there. The driver may need to retain control even if the car can make most of the decisions, he said.

While Google envisions a car that will let drivers in California save on a hotel stay while driving the back roads to ski at Lake Tahoe from their homes in the Bay Area, Toyota foresees a car that will be so smart it will react before a driver can to prevent a crash.

“For us, autonomous is not synonymous with driverless,” Gulash said on the SAE panel. “The driver needs to be in control. We’re developing technologies on a continuous basis to provide more assistance to the driver.”